Absorption refrigeration apparatus



Jan. 2551944 J. N. Ro'rH- r-:rAL 2,339,812

i ABSORPTION'REFRIGERATION APPARATUS Filed 001".v l5, 1939 5 Sheets-Sheet 1 Jam 25,1944. A 1N, RO-THhErAL 2,339,812

ABSORPTIN REFRIGERATION APPARATUS Filed oct.' 5, 1939 s sheets-sheet 2 www lll/ll mm zgn 9 Al vtion described herewith Patented Jan. `25, 1944 Joseph N. Roth, Boldi Sohurtz', Kansas City, Mo., assignors, to Gibson Refrigerator assignments,

Greenville, Mich.,

ng, Mich., and Ralph E.

by mesne Company,

.a corporation of Michigan .ippuoouon` ootob'er 5, 1939, serial No.v 298,119.

' .zo claims. (c1. 62-5) This'invention relates to absorption refrigeration apparatuajand more particularly to a systemadapted to Amaintain the still at a high pressure and the absorber at a low pressure and to eifect return of liquor bottom of the sun to me absorber and nowof rich liquor from thebottom of the absorber tothe still. This latter means includes a transfer from the absorber to the still'through an intermediate transfer charm' ber One feature of this invention is that improved transfer means for returning the rich liquor to the still is provided; another feature of this invention is thatv it ment in operation in a system oi the type whereporuon of the system' and to a low pressure portion; a further feature is that means are provided for fluid fromA the transfer chamber when it is connected to the low pressure portion .of the system after it has been connected to the high pressure portion; yet

another feature of this intem schematically or provides considerable improve-v` subduing the rush ofA ventionis that it provides morepositive movement of'iluid from the absorber to the transfer chamber; and still vanother feature of this invention is that it` causes Y the valve means associated with the transfer chamber to withstand the full pressure differential in thesystem for only a brief period. Otherfeatures and advantages of this invention will be apparent from the following specification which:

Figure l is a schematic or diagrammatic showing of refrigeration apparatus embodying this invention; Figure 2 is a detail sectional view of the pressure chamber; Figure 3 is a fragmentary sectional view along the-line 3 3 of Figure 2; Figure 4 is a detail sectional view vof the check valve, along the line 4 4 offFigure 2; Figure 5 -alid the drawings, in.

enclosing the flue Both the analyzer chamber intermediate the absorber. and the still and a valve arrangement whereby the chamber is selectively connected to the absorber or to the still.

Referringmore particularly to a specific syscliagrammatically illustratedin Figure 1,-the still I 0 Vis adapted to contain a mixture of water and ammonia. A flue Il is provided within the still and heat delivered thereto by the combustion of gas or some other fuel delivered bythe burner I2. An analyzer tower I3, in the form of a long Ii, rises from the upper part of is a vertical cylindrical vessel. tower and the still are provided with baille plates, as I4 and I5, these plates serving to stratify the liquid in the still and to improve the eiciency of the apparatus.

Rich ammonia vapors boiled oithe liquor in the still pass upwardly through the analyzer the still, which tower I3 and then through the pipe connectiony crease the heat radiation. 'I'he ammonia vapor ishere condensed`into liquid ammonia, and then is a 'vertical sectional view of al modied arrangement of absorber and Figure 6v is a vertical sectional view of still another modification of this invention.

In .the particular embodiment of' our invencomprises a still adapted toh'ave a mixture of refrigerant and absorbent, as` ammonia and thereby; an evaporator or cooling unit in. which the liqueiied refrigerant is permitted to vaporize. the. evaporator having restricted connection with 'evaporator is reabsorbed in liquid; and r'eifecting now of weak liquor from the and pressure chamber:

the system in general liquid ammonia ris elevated by the vapor pressure behind it through the connection 20 to the receiver 2|.'

The amount of ammonia boiled oli' and liqueiledis a function of theconcentration -of the liquor in thestill and of the amount of heat supplied to it, so that if the concentration of liquor is kept relatively constant the rate of delivery of liquid ammonia to the receiver 2| will be pracof the amount of heat stat in the cooling chamber of the refrigerator.

Liquid ammonia passes from'th'e receiver 2| to the dryvevapo'rator eral coils of piping,

22, preferably comprising sevl through the posed by' a valve 23 controlled by the float 2l. The'noat and valve are so arranged that,` as more Velive'recl to the receiver, the

cylindrical tubing any entrained water vaporhaving been This condenser comprises one or more loops of piping, finned to in-` restriction intersure, the rich liquor lyaer tower and thence to until the valves the evaporator to maintain the level of liquid in the receiver substantially constant.

Absorbing apparatus is provided in the form of an upper chamber or vessel 25 having extending .downwardly therefrom a cooling and absorption loop. This loop is formed by a pipe 26 extending down from the bottom of the absorber vessel; the absorber cooling coil 21, finned for better heat radiation; and the upwardly extending pipe or leg 28, terminating in the vessel 25 slightly above the level of absorption liquid therein.

Expanded ammonia vapor from the evaporator 22 first passes through a small loop or coil 29, the purpose of which will be hereinafter-explained, then through the pipe 39 into the rising leg 28 of the absorber loop, near the lower part thereof. The incoming vapor creates bubbles in the leg 28 of the absorber loop which provide a liquid lift or pump insuring circulation of absorption vliquid through the loop.

in this rising leg is at all times the weakest liquor in the absorber, and cool as a result of passing through the coil 21, all absorption takes place in the pipe 28 under normal conditions, the liquid ilioging out of the top of this pipe Vbeing quite r c The level of liquid in the absorber vessel 25 is maintained by a float 3| and valve 32 controlling delivery of weak liquor from the still. The pipe 33 leads from the lower end of the still (where the liquor is weakest) through a heat exchanger 34 and then on up to open into the absorber, the flow into the absorber being controlled by the valve 32, which opens whenever the level of liquid in the vessel 25 drops below a desired point.

The means vfor returning rich liquor from the absorber to the still comprises as its principal parts a transfer chamber 35, a valve assembly 35, a pressure chamber '31 and associated opera'.- tive interconnections. A flow connection is provided from the leg 23^^of the absorberloop, out of the short open-ended cross tube 28a, through the Jacket 33, pipe 39, and check valve I0, into the pressure chamber 31. When the valves are set in a certain position a flow path is provided from the' pressure chamber, and thus from the absorber, through the pipe Il, the valve mecha-I nism, and the pipe 52 to the bottom of the trans- -fer chamber 35,- any vapor therein being vented through the pipe 43 andthe .pipe Il (interconnected by the valve assembly) into the pressure chamber.

' When the valve device is actuated, in accordance with a condition of the system, to move the valves to another position, the pipe 431s connected to the pipe 45 which is open to high pressure vapor in the pipe I3; and the pipe I2 is connected to the pipe l5, connected through the heat exchanger 3l, to a Jacket 41 around athermostat bulb in the still, andthen through a pipe I3 into the analyzer tower. The transfer charnber and connecting pipes now being at high prestherin-,nows intothe anaare again moved to the rst described above.

When the interconnection between the pressure Y chamber and the transfer chamber is again provided there is, of cdurse.' a rush of high pressure 'vapor through the pipes'arid 4I to the chamber 31. The check valve I0, however, prevents these vapors from getting back into the low pressure side of the system; and the liquid in the chamber 31, cooled by the coil 29, rapidly absorbs Inasmuch as the liquid of weak liquor bled into the vapor, assisted in this respect by a fine stream the chamber 31 through the conduit I9 branching from the weak liquor .pipe 33. The rapid absorption of rich ammonia vapor causes the pressure in the chambers 35 and 31 to drop below the pressure in the absorber 25 for` a brief time, so that there is a positive pressure-driven flow of rich liquor from the absorber to completely reiill the chambers 35 and When these are completely filled with liquid the weak liquor entering through the branch pipe I9 immediately starts to raise the pressure therein,

' the check valve 40 closing; and shortly the chama loud hissing or sometimes difcult to secure the bers 35 and 31 will again stand at high pressure. There is thus only a brief interval during which the valves in the assembly 35 must withstand the full difference of pressure between the high and low sides of the system.

While the continuously operating absorption refrigeration apparatus above described contains a number of inventions and improvements over' other known systems, this present application is particularly concerned with the pressure chamber and its associated parts and functions. Other improvements in the system are being made the subject matter of the earlier led Roth application Serial No. 296,995 and other co-pending applications by the present inventors, both jointly and severally.

' We have found that refrigerating apparatus adapted to maintain the still at high pressure and the absorber at low pressure and to return liquor to the still by alternately connecting a transfer chamber first to the absorber and then to the still, particularly when designed in a size adapted 'for use in the domestic refrigerator, is'open to several undesirable objections.

' In the rst place, the pressure in the high side of the system is frequently 200 or 250 pounds per square inch, while that in the low side is in the neighborhood of atmospheric pressure. When the transfer chamber, after having been connected to a high pressure portion of the system. is connected to a low pressure portion thereof, there is an initial rush of fluid, in the form of refrigerant vapor, from the transfer chamber into the low pressure side of the system. I'his is highly undesirable for a number of reasons. It causes rushing noise, objectionable in a domestic refrigerator, for example; discharges ammonia vapor at high pressure into the absorber, which should only have to carry the load of absorption of vapor from the evaporator; and otherwise disturbs the smooth and emcient operation of the system.V Moreover, vertical space in a domestic refrigerator is limited, and it is desired flow of liquid from the absorber to the transfer chamber while at the same time having the transfer chamber high enough above the 'still to maintain Va good delivery head. Moreover, it is preferable to have the transfer chamber disconnected from the high pressure side of the system several times as long as it is connected thereto, as for example in the ratio of about eight to one. Under these circumstances, the valves associated with the transfer chamber have heretofore had to 'maintain across themselves the full pressure differential of the system for considerable periods of time.

we have obviated these and other objections in continuous absorption refrigeration apparatus of the type herein disclosed by providing a pressure chamber 'in the connection between the absorber and the transfer chamber. We so arrange matfor a period embodiment of our invention .the weak liquor pipe 33 the bore of a cooperating After the initial rushgof uid the pressure inthe by reason of absorption pressure chamber drops, y therein, to a'pressure lower than that existing in the absorber, so that ow of liquid from the absorber to the pressure chamber and thus to the means provided for absorbing this vapor: bsforption being greatly accelerated by the small stream of weak liquor flowing in through the bleeder or by-pass orifice 49 whenever the pressure inthe pressure chamber is below thatv in the high side of the system. This bleeder orice or conduit has a liquid delivered is notsuflicient to create any contransfer chamber, is positive.- Immediately after the transfer chamber and pressure chamber have refilled with rich liquor from the absorber the `pressure in the and shortly equals that in the high side of the pressure chamber starts to rise.

systenf. The valves associated with the transfer chamber thus need maintain the ill pressure dierential of the system thereacross for only a brief part of the total period of time that the transfer chamber is disconnected from the still'.

Referring more particularly to the particular illustrated in Figures 1 -to 4, it .will be seen that a liquid flow path is provided' from the absorber through its cooling loop, through the casing 33, the pipe 39, and the check valve 40 into the pressure chamber 31;

and that this liquid iiow path continues on into the'transfer chamberwhen the valve mechanism isso arranged as to connect the pipes 4I and 42.

Vapor from the top of the transfer chamber is vented through the pipe-43 and the pipe 44 into the pressure chamber. 'I'he check valve 40 is here shown as a small plate urged by gravity against its` s eat 5I; and so arranged that liquid can flow from the absorber to the pressure chamber, but cannot iiow in the reverse direction. The by-pass or bleeder conduit 49 branching from I is here shown in one cori?- venient form of construction wherein it has a portion with avery small opening. This is attained by grooving a plug 52 and driving it into cylindrical member 53.

When the transfer-chamber has been connected to the still and delivered in to it, the pressure in the and the pressure difieren ial acts through the liquid actuating leg 55 to throw the valves inthe valve assembly 33 to a position disconnecting the pipes 45 anclv 43 and connecting the transfer chamber to the pressure chamber, andthus actuating bulb drops,

s iderable change in the volume of liquid in the pressure chamber, the restricted portion of the conduit, in one refrigerator we have built, having a diameter of `only .006 inch. The weak liquor sprayed in through this orifice, however, greatly n accelerates the absorption of ammonia vapor, so that in amater of -seconds afterthe initial rush the pressure in the chambers and 31 has dropped to perhaps ve pounds or morebelow the pressure in the absorber.

As soon as this occurs there is a positive pres.

v-sure driven flow of liquid from the absorber past vthe check valve Vand then down through the pipe 4I to the into the pressure chamber,

transfer chamber, until both the transfer chamber and the pressure chamber are again completely refilled with liquid, any traces of ammonia vapor which would' otherwise be trapped at the top being absorbed by the fine stream of liquor entering through the conduit 49.

weak s soon as the chambers andconnecting vpipes are again completely filled with liquid, the continued admission of weak liquor begins to have an appreciable effect. liquor causes the This stream of weak pressure in the pressure chamber and transfer chamber'to rise, the check valve' 40 preventing any flow of fluid from the pressure chamber to the absorber. onds after the chambers are completely filled with liquid the pressure in them has risen substantially to that in the high side of the-system,

most of the liquor therew in assuring ing if the .through it to the absorber. 'flThat is, in this position the ends"o`f pipes 45 and 46 are blocked; pipe 43 is connected to pipe 44; and pipe 4I is connected to pipe 42. ber is filled with fluid at high pressure there is an initial rush of 'ammonia vapor, into the pressure chamber 31. The pressure chamber 31 is,

however, full of liquor: at high pressure which has been. held in-it while the 4transfer chamber was connected to the still.y The initial rush of vfluid fr'omthe transfer chamber is .thus subdued `Aby absorption in a', solid body of liquid in a chamthe transfer chamber iilling the space in the pressure chamber above the` liquid. The surface ofthe liquid is not theonly Since the transfer cham- 'the' fact that the pressure so that the valves in the longer have the complete the system across them. Instead, both sides of the'valve's are nosw at substantially equal high pressure; and the pressure difference between the high and low sides of the system is across the check valve 40. There is, of course, no diliculty the desired seal and long life of the check valve 40; but movable valves of the kind in the valve assembly 36, whether of the plunger or slide type, have excessive wear and wire drawfull pressure difference is maintained 'across them. Moreoverf the vfrictional wear caused by movement of the slide valve, for example, andthe resistance which it interposes to the actuating mechanism,his greatly reduced 'by on both sides is practically equal whenever there `is movement of the valve. 1

The transfer chamber ,thus stand at high the period that the transfer chamber is disconnected frbm the still. When the liquid 'inthe still has boiled down to a'predeternined concentration which, by means of the actuating bulb 54, effects movement of the valves ini'the assembly 36, the transfer chamber, 35 is aga/in connected to the still. That is, pipe 42 is connected to pipe 46; pipe 43 is connected to pipe 45;. and pipes 4| and 44 are blocked. High pressure vapor entering through the pipe 45`insures complete equalh ization of pressure in the still and transferchamber While the liquid therein flows through. the pipes 42 and 46, the 41 around the actuating bulb, and the pipe 48 into the 'analyzer tower I3, and thus into' the valve assembly 33.110

and pressure chamber portion in it so small that the volume of In a matter of secpressure differential of .Y

pressure for the remainder ofleat exchanger 34,'.the jacket still.

that and The arrangement is preferably such the transfer chamber drains fairly rapidly,

' after'about two-thirds of the liquid therein has 'passed into the still, as for example in about 45 seconds, the position 'of the valves is changed and the transfer chamber reconnected to the pressure chamber. The initial rush of vapor, the drop in pressure below the absorber pressure, the flow of liquid from the absorber until the chambers are again completely filled, and the rise in pressure, all take place in lless than a minute, although in normal operation of the system the transfer chamber is not again connected to the still for seven or eight minutes.

In the modified form 'of our invention illustrated in Figure 5, the pressure chamber 60 lies within the shell of the absorber 8 I, although it is connected to it only by the liquid connections $2 and the riser 63, being otherwise completely sealed from the remainder of the absorber. As in the preceding form of structure, circulation ofi absorption liquid is maintainedat all times dur-i ing evaporation down through the pipe 64, through the absorber cooling coil, not shown, and up again through the pipe 65.` The pipes Sii` and 61 opening into the pressure chamber- 60 correspond with the pipes 4i and 44 described in the 'structure shown in Figures 1 in 4. Cooling Vof the fluid in the pressure chamber is again achieved by passing vapor, on its Way from the evaporator to the absorber, through the cooling coil 68. A check valve 69 is provided in the pipe 62, so that liquid can flow only from the rising leg of the absorber coil into the pressure chamber; and cannot flow in the reverse direction. The riser pipe 63 extending upwardly from the pressure chamber has in the upper portion thereof a restricted or capillary conduit 10, preferably terminating about a half-inch below the level at which the liquid is maintained in the absorber by the valve 1I and float 12. 1

In this form of.our invention'the pressure chamber is again filled with liquid at the time when the Atransfer chamber is connected to it; and ow of uid from the pressure chamberto the absorber is restricted by the check valve -69 and the capillary orifice 10. The high pressure vapor from the transfer chamber thus again strikes a solid body of liquid which almost immediately jumps to high pressure, thus subduing the rush. In this form the pressure in the transfer chamber is reduced by absorption therein, and

' by bleeding of the gas through the capillary 10 into the absorber proper. The fact that the pressure chamber is cooled to a temperature lower than that of the absorber causes the pressure in it to drop below that in the absorber upon substantially complete absorption of the vapor; and. ow of liquid then takes place past the check-.4 valve It until the pressure and transfer cham* bers are completely refilled. Any residual vapor is bled'off through the conduit 1U; and any gas or. vapor is prevented from being trapped by thel fact vthat there is such a slight head of liquid thereabove.

In the further form of our invention shown in Figure 6, the pressure chamber again lies within the shell of the absorber 18, although it is connected tothe remainder of the absorber only through two connections, each having valves therein. One connection is past the check valve 11 and through the pipe 18 to the rising leg 19Y of the absorber cooling loop; and the other connection is through the riser 80 and past the valve llwwhisuvalve is normally pressed down away Uyl/4., l

from its seat by the spring 82. preferably so arranged as to keep the valve open whenever the pressure in the pressure chamber is not more than ten pounds above that in the absorber. Pipes 82 and 83 again correspond to pipes Il and 44 in the modification of this invention first described.

.pounds of that in the absorber, the valve 8| is opened by the spring 82, and the pressures in the pressure chamber, transfer chamber, 'and absorber, thereupon equalized. Flow of liquid thereliquor from'the latter upon takes place into through the pipe 18 In all of these forms, in the absorber controlled valve which admits weak liquor from the still whenever the liquid level in the absorber drops.

While we have shown and described certain embodiments of our invention, it is to be underthe pressure chamber, both and through the riser 80. of course, the level of liquid lstood that it is capable of many modifications.

Changes, therefore. in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

We claim: i

1. Absorption refrigeration apparatus of the character described adapted to provide continuous refrigering effect, including: a still; a cOndenser, the still and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorber being adapted to operate at low pressure; `a transfer chamber,l adapted to be connected alternately to the still and to the absorber to effect return of liquor from the latter tothe former; a pressure chamber in the connection between the transfer chamber and the absorber for subduing the rush of fluid from the transfer'chamber when it is connected to the absorber; and operative connections between the elements of the apparatus.

2. Absorption refrigeration apparatus of the 4 character described adapted to provide continuous refrigerating effect. including: a still; a condenser, the still` and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorber being adapted to operate at low pressure; a transfer chamber adapted to be connected alternately to the vstill and to the` absorber to effect Vreturn'of to the former; a pressure chamber in the connection. between theV transfer chamber and the absorber adapted to be'fllled with liquid when' the vconnection of the transfer chamber to the absorber is effected to subdue the rush of fluid from the transfer chamber; and operative connections between the elements of the apparatus.

3. Absorption refrigeration apparatus of the character described adaptedqto provide continuous refrigerating effect.' including: a stil1;a condenser, the still and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorber being adapt- .ed to operate at low pressure; a. transfer c ham-v v ber adapted to be connected alternately to .the

proper is maintained by the float chamber in the connection between the transfer chamber and the absorber adapted to be illled with liquid when the connection of the transfer chamber to the absorbed is effected tosubdue the rush of fluid from the transfer chamber; a connection between the absorber and the pressure chamber for a now of liquid from the former to the latter, but wherein a check-valve prevents flow in the other direction; and operative con-- nections between the elements ofthe apparatus.

4. Apparatus of the character claimed in claim 1, including means for introducing weak liquor into the pressure chamber. 5. Apparatus of the character claimed in claim 3, including means for supplying a small stream of weak liquor to the pressure chamber when the pressure therein is below that in the still.

6. Apparatus of the character claimed in claim 3, including a second restricted connection between the pressure chamber and absorber.

7. Apparatus of the character claimed in claim 3, including a second connection between the@ pressure chamber and absorber having a valve therein adapted to close when the pressure in the pressure chamber is materially higher than that.

in the absorber.

..8. Apparatus of the character claimed in claim '3, including a second connection between the pressure chamber and of very small diameter. s 9. Apparatus of the character claimed in claim 3, including means for supplying a` small stream of weak liquor to the pressure chamber when the pressure therein is below that in the still and means for cooling the pressure chamber.

` l0. Apparatus of the character claimed in claim 2, including means for passing at least a. portion of the refrigerant fluid in heat exchange relation with the contents 1l. Absorption refrigeration apparatus of the character described adapted to provide continuous refrigerating effect, including: a still; a con-` denser, the still and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorber being adapted to operate at low pressure; a. transfer chamber; valve means having a movable valrve member adapted to stand valve means in one position connecting the transfer chamber to the absorber and blocking connection to the still and in the other position connecting the transfer chamber to the still and blocking connection to the absorber, to eiect retum4 of liquor from the absorber to the still;

absorber having a portion means between the valve means and the absorber so constructedand arranged that the full pressure drop between the still yand the absorber exists across the valve means foronly a brief period; andv operative connections between the f elements of the apparatus. l I 12. `Absorption refrigeration apparatus of the character described adapted to provide continuous refrigerating effect, including: a still; a con# denser, the still and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorberbeing adapted to operate atl low pressure; a transfer-chamber; valve means for alternately connecting the transfer chamber to the still and blocking connection to the absorber, andyice versa, to eect return of liquor'from the absorber to the still; a presbetween the valve sure chamber in the connection means and the absorber;

pressure in the pressure means `for raising the chamber, shortly after connection of the transfer chamber to the ab- 76 ya check-valve preventing flow of fluid fromthe sorber, to that of the still; and operative connections between the elements of the apparatus.

13. Absorption refrigeration apparatus of the character described adapted to provide continuous refrigerating eilect, including: a still; a condenser, the still and condenser, beingadaptedA to operate at high' pressure: an evaporator; an ab-v sorber, the evaporator and absorber being adapted to operate at low pressure; a transfer chamber; valve means for alternately connecting the transfer chamber to the still and' blocking connection to the absorber, and vice versa, to effect return of liquor from the absorber to the still; a pressure vchamber in the connection between' the valve means and the absorber, the connection between the pressure chamber and the absorber including former to the latter; means for supplying a small stream of fluid from a high pressure portion of the apparatus to the pressure chamber to raise the pressure therein, shortly after connection o'f. the transfer chamber to the absorber, to that of V the still; and operative connections between the velements of the apparatus.

14. Apparatus of the character claimed in claim l2, wherein the transfer chamber is disconnected from the still for a period several times that during which it is connected thereto.

15. Absorption refrigeration apparatus of the character describedadapted to provide-continuofthe pressure chamber.

in either of two positions, the

absorber so constructed ous refrigerating eifect, including: a still; a condenser, the still and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorber being adapted to operate at low pressure; a transfer chamber; valve means for alternately connecting the trans-` fer chamber to the' still and' blocking connection thereto; means between the valve means and the and arranged that the full pressure drop between the still and the absorber exists across the brief period; and operative connections between the elements of the apparatus. v

16. Absorption refrigeration apparatus of the character described `adapted to provide continuous refrlgerating eiectincluding: a still; a condenser; the still and condenser being adapted to operate at high sorber, the evaporator and absorber being adapted to operate at low pressure; a transfer chamber; a connection between the transfer chamber and the absorber; valve means for alternately connecting the transfer chamber to the still vanal lblocking connection thereto; means for rst lowering 'the pressuren the transfer chamber and then raising the pressure and blocking the connection to the absorber shortly after the connection" to the/still is blocked, whereby the full pressure drop' between the still and the absorber esistsacross the 7valve meansI for only a brief period; and operative connections between, the elements of the apparatus. 3

l1"l. Absorption refrigeration apparatus ofthe character described denser, the still and condenser being adapted to operate at-high pressure; an evaporator; an absorber, the evaporator and absorber being adapted to operate at lower pressure; transfer means: conduits having positively operated transfer valve means therein for alternatelyconnecting the transfer means to the still and for closing such connections; a connection between the transfer -means and the absorber including a check valve preventing now oi'r fluid from the" former to the latter; a conduit for supplying a Valve means for only apressure; an evaporator; an abadapted to provide 'continu small stream of weak liquor from a high pressure portion of the apparatus to the transfer means, this conduit being unrestricted except 'at its point of connection to the transfer means; and actuating means including a thermally responsive element in heat exchange relation with Athe contents of the still and connected to the positively operated valve means for shifting the latter in response to change in a condition in the still; whereby the stream of Aweak liquor, after the positively operated connections are closed, first causes the pressure in the transfer means to drop below that in the absorber to ll the transfer means with liquor from the absorber, and than raises the pressure in the transfer means substantially to that in the still to prevent application of the full pressure differential in the system to the positively operated valve means for long periods while it maintains the connections closed; and operative connectionsbetween the elements of the apparatus.

18. Absorption refrigeration apparatus of the character described adapted to provide continuous refrigerating effect, including: .a still; a condenser, the still and condenser being adapted to operate at high pressure; an evaporator; an absorber, the evaporator and absorber being adapted to operate at low pressure; means adapted to be connected alternately to a high pressure portion and a low pressure portion of the apparatus; a body of liquid at high pressure; means for providing connection between the first mentioned means and the body of liquid and isolating both from the remainder of the apparatus before completing the connection to the low pressure adapted to be connected alternately to the still and to the absorber to eiect return of liquor from the latter to the formeraa pressure chamber in the connection between the transfer chamber and the absorber, normally filled with liquid at high pressure; means forblocking connection between the transfer chamber and the still and connecting the transfer and pressure chambers;

means for subsequently completing connection of l the transfer chamber to the absorber; and operative connections between thev elements of the apparatus.

20. Absorption refrigeration apparatusy of the character described adapted to provide continuous refrigerating effect, including: a still; a condenser, the still and condenser being adapted to operate at high pressure; an evaporator: an absorber, the evaporator and absorber being adapted to operate at low pressure; transfer means adapted to` be filledv with liquor from'the absorber; means connecting the transfer means to the absorber, including a check valve permitting ow only to the transfer means; conduitshaving positively operated valve means incorporated K o5 therein for providing liquor and vapor connections between the transfer means and the still to deliver liquor thereto, and for closing such connections; means for deliverlnga fine 4stream pfvweak liquor at substantially still pressure to the transfer means; and actuating means including a thermally responsive element in heat exchange relation with the contents of the still and connected to the positively operated valve means for shifting the,latter in response to :i5 change in a condition in the still; whereby the stream of weak liquor, after the positively operatedconnections are closed, iirst causes the pres-j sure in the transfer means to drop below that in the absorber to fill the transfer means with 40 liquor from the absorber, and then raises the pressure in the transfer means substantially to that in the still to prevent application of the full l pressure vdifferential in the system to the positively operated valve means for long periods while it maintains the connections closed.

JosEPH N. Rom. e f RALPH E. scnca'ra 

